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Torque values
Posted:
Mon Jul 13, 2009 10:17 pmby jonevansmidas
On looking through the various workshop manuals, there appears there may be some variation between the torque required to instal say, a cylinder head stud in the block and the torque to tighten the nut on the cylinder head. Looking at the thread sizes, it appears that the stud torque may be about 75% of the nut torque.
I realize that Adrian Dodd has the touch, but I have three torque wrenches which are calibrated and I need to use.
Should the two torques be the same, bearing in mind that the stud may have Studlock applied and the nut Nutlock applied?
Re: Torque values
Posted:
Mon Jul 13, 2009 11:26 pmby manifold
I've never bothered checking the stud torque myself.
Always checked the studs screw home into their respective holes to the end of their depth, then applied torque to the nuts as per the manual. ie 50lbs on cylinderhead nuts.
its always worked for me.
cheers,
david
I never use thread lock on cylinder head, but neither do I oil them either. just dry and cleaned threads.
Re: Torque values
Posted:
Thu Jul 16, 2009 11:03 amby ACDodd
Studs hand tight only.
AC
Re: Torque values
Posted:
Thu Jul 16, 2009 9:54 pmby jonevansmidas
Many thanks Adrian - that would explain a lot!
Cheers
Jon
Re: Torque values
Posted:
Wed Nov 04, 2009 6:33 pmby gooseman
Some years ago i worked at a materials testing laboratory & we did quite a lot of fastener testing, a lot of yield/tensile tests on full size bolts up to 1.5" diameter and reduced sections for sizes above that, this was done on massive hydraulic machines. We also did torque wrench calibration but these were huge wrenches for bridge construction however i did test a cheap wrench i had bought for less than $20 & it was very accurate to 150 ft/lb.
There was always controversy about the relationship of torque to actual tension in the fastener itself & we had a device called a Skidmore-Wilhelm tester. This was a hydraulic device with a pressure gauge attached & the fastener was fitted into the center of it & tightened to the appropriate torque value, the gauge would tell the tension that was exerted.
I planned to fit some ARP studs to my Fiero V6 in preparation for turbocharging it so i brought the Skidmore/Wilhelm home so i could check the values & subsequently did more than a hundred tests on the studs. I tried several different lubricants on the threads even a slippery assembly lube to look at the values i would get.
What im getting around to saying is that you need to use at a minimum some 10w30 oil on any & all threads when you torque (or otherwise) to achieve a proper value NOT just screw them up dry...jim